The present invention relates to a substrate transfer apparatus for transferring a printed substrate with a movable handler, which may be provided in an ultraviolet ray exposing apparatus.
In a UV ray exposing apparatus or other exposing apparatus, one of the methods for transferring a substrate carried by a carrying-in roller onto a mounting table and transferring a substrate exposed on the mounting table to a carrying-out roller is holding the substrate by a handler which is provided to move freely while transferring.
Here, in order to hold the substrate, a handler having a plurality of vacuum pads is used, and the sucking force is applied to the surface of the substrate attached to the vacuum pads to vacuum and hold the substrate.
With the above method of attaching the vacuum pads to the surface of the substrate, because the strong sucking force is applied partially on the surface of the substrate, the following problems arise.
a) In a case that coating agent (ink, resist or others) coated on the substrate is half-dried, the substrate may not be held.
b) In a case that there is the coating agent filled in a through hole penetrating the substrate, the coating agent may be sucked and removed.
c) In a case that the surface of the substrate is uneven that the dust is on the surface of the substrate, it may affect the hold of the substrate.
d) In a case of the thin substrate, the substrate may change its shape and the marks due to vacuum may be remained on the substrate where the vacuum pads are attached.
e) In a case of the thin substrate, the substrate may be bent where the vacuum pads are not attached.
As a method of holding the substrate which does not arise the above problems, there is a method disclosed in the Japanese Patent Laid-open No. 7-9269. This method is that a handler comprising a plurality of vacuum pads having a function of applying tension and a plurality of Bernoulli chucks which are noncontact chucks is used and that the sucking force is applied to the circumference of the surface of the substrate where the vacuum pads are attached and that the circumference of the substrate is vacuumed to be held and that the negative pressure occurs at the top surface of the substrate to which the Bernoulli chucks are faced to hold the top surface of the substrate without contacting the surface of the substrate and that the tension is applied between each of the vacuum pads so that the substrate is not bent.
According to this method, the top surface of the substrate is held by the Bernoulli chucks without contacting the surface of the substrate, so that the above problems a), b), c), d) do not arise. Further, since the tension is applied at the circumference of the substrate by the vacuum pads, the problem e) does not arise.
However, with the method disclosed in the Japanese Patent Laid-open No. 7-9269, since the circumference of the substrate is vacuumed with the vacuum pads, the problems a), b), c), d) still arise.
Further, in order to perform the prealignment for aligning the position of the substrate on the mounting table with the position of the mask pattern, an additional alignment mechanism needs to be provided at either the carrying-in roller or the mounting table. Accordingly, the structure of the apparatus becomes complicated and the process increases.
Therefore, it is an object of the present invention to provide a substrate transfer apparatus which transfers the substrate without contacting the substrate and which does not need the additional prealignment mechanism.
A substrate transfer apparatus of the present invention comprises a handler for transferring a substrate. The handler comprises a substrate holding apparatus comprising a noncontact chuck for holding the substrate without contacting a surface of the substrate, and an elevating mechanism for lifting and lowering the noncontact chuck, and a substrate contact apparatus comprising a contact member to be in contact with an end face of the substrate, a moving mechanism for moving the contact member away from the end face of the substrate as the noncontact chuck is lowered and moving the contact member towards the end face of the substrate as the noncontact chuck is lifted. Here, the handler may comprise a plurality of the substrate holding apparatus and a plurality of the substrate contact apparatus.
Accordingly, the substrate can be held by the noncontact chuck without contacting the surface of the substrate. Moreover, the forward and backward movement of the substrate can be regulated by the contact member.
Further, the contact member may comprise an angled surface for aligning and holding the substrate by being in contact with the end face of the substrate.
Accordingly, the substrate is aligned by the angled surface is which also holds the end face of the substrate. Therefore, since the contact member performs as the aligning member, the additional prealignment mechanism is not required. Moreover, since the contact member also performs as the holding member, even if the operation of the noncontact chuck is terminated, the substrate can stably be held.
Furthermore, the contact member may comprise a supporting member for supporting the substrate by being in contact with the lower surface of the substrate.
Accordingly, the lower surface of the substrate is supported by the supporting member, so that the substrate can be supported without the end face of the substrate to be pushed. Moreover, even if the operation of the noncontact chuck is terminated, the substrate can stably be held.
Further, the moving mechanism comprises a guide for supporting the contact member to be moved in a horizontal direction, a spring for pushing the contact member towards the end face of the substrate, a ball provided in the contact member so as to be rotated, and a bracket to be lowered and lifted connected with the lowering and lifting of the noncontact chuck, provided with a tapered surface to be in contact with the ball to move the contact member.
With this structure, the bracket is lowered as the noncontact chuck is lowered. Then, the ball rotates at the tapered surface, and the contact member is moved along the guide away from the end face of the substrate due to the force of the spring, which means open. Next, the bracket is lifted as the noncontact chuck is lifted. Then, the ball rotates at the tapered surface, and the contact member is moved along the guide towards the end face of the substrate due to the force of the spring, which means closed. Accordingly, the lowering and lifting of the noncontact chuck can be connected to the opening and closing of the contact member with the simple structure.
Furthermore, the substrate transfer apparatus may further comprise a first carrying roller for transferring the substrate, a mounting table for mounting the substrate transferred by the first carrying roller, and a second carrying roller for transferring the substrate after the substrate is exposed on the mounting table. Here, the first carrying roller and the mounting table comprise an air nozzle for blowing compressed air towards the lower surface of the substrate when the noncontact chuck is lowered.
With this structure, when the noncontact chuck is lowered to hold the substrate, the air nozzle blows the compressed air to the lower surface of the substrate. Accordingly, even if the coating agent is half-dried and the viscosity of the surface of the substrate is high, the substrate can easily be removed from the carrying roller. Moreover, even if the substrate is adhered to the mounting table, the substrate can easily be removed from the mounting table.